Production of photographs in blue tones



Patented se r. 1a, 1945 2,384,897

um'rso STATES PATENT OFFICE PRODUCTION OF PHOTOGRAPHS 1N BLUE TONES Fritz Dersch amlNewton Heimbach, Blnghamton,

N. Y., assignors to General Aniline & Film Corporation, New York, N. Y., a corporation of Delaware No Drawing. Application June 25, 1942,

Serial No. 448,416

e 6 Claims. (Cl. 95'6) This invention relates to a method for produc- (JO-NH ins developed silver bromide pictures from silver C H bromideb emulsions, and more particularly to a o method 37 which said developed pictures are produced with a blue-black tone. I 5 methymmm Many organic compounds have been suggested C NH from time to time for producing a blue toning f- (some JJ=/S feet on silver chloride emulsions. Thus triazole, quinine and similar compounds have been em- Dibutylthiobarbituric acid ployed for this purpose. Such compounds, how- 1 ever, have little or no effect on the tone of a J J silver bromide emulsion. Very few agents are O =8 mentioned in the literature as blue toners for bromide emulsions. A condensation product of V lBemmhmba'bnm acid cystine and formaldehyde has been suggested for this purpose, but this particular compound is me (i=8 known to cause serious fogging.

With. this prior art in view, it is accordingly one fififi gfi we objector the present invention to provide a new 00 NH process for the production of blue-black tones in silver bromide emulsions. C =5 A furtherobject is to provide a. new class of blue toning agents for silver bromide emulsions 'benmmmlmihmbmmmc acid which will-not have a serious fogging efiect. oo-rm Another object is to provide a new class of blue 0 $=g toning agents which may be incorporated directly into a light sensitive silver bromide emulsion. 1. hy1.5.ba m1-5-imh;thl hnrbitui-ie scid An additional object is to provide su h agents (IO-NH which may he added to a photographic developer. J: (g

Either objects and advantages of the present Q accomplished by the use of a new class of cominvention will be readily apparent from the fol- HN=(!)-- lowing description. 1

-phcnyl-5-benzsl-6-iminothiober mu 0 said l are Ne have found that the foregoing objects In order that those persons skilled in the art p I mmme may fully understand the purpose end scope of fifie fo ei 32:5 sf z fipi n l s he fol s invention, the following detailed examples lowing iormula: are given: Example I X- it. metoi-hydroduinone developer of the follow- R.=o is ins composition is prepared: X: -N-Y 7 Metol Sui arns..- i5 im R seeds for hymen, itifdfumiifi i::::::::::::::::::S3:::: stands for O or NH; and Y stands for hydrogen, 45 Sedmm gamma 49 aiin l, or aryl; it equals 1 in t e 5? of Mal and 2 Potassium bromide d0 2 in the case of hydrogen and allzyl. Water to make cc. 1750 Typical compounds corresponding to the above To this developer solution there are added 125 formula Whioil are included in this invention are mg of diethymmobmmtuflc mm Upon develop mmws; ing a normally warm toned exposed elatino silverbromide emulsion film. in this developer, blue l 5 tones will be produced in the silver image.

, Emmpte l'i' to A metoi-hydro ulnone developer or the same composition as Example Iis prepared. To this developer there are added 125 mg. of dibutylthiobarbituric acid. Upon developing a normally warm-toned exposed gelatino silver bromide emulsion film in this developer a blue toned silver image is obtained.

Example III To 1 kilogram of a gelatino silver bromide emulsion there is added, prior to the coating,"75 mg. of

5-ibenzal-6-iminothiobarbituric acid. Exposure and development of this emulsion in an ordinary developer such as the metol-hydroquinone developer of Example I will yield a silver image having a blue tone. Any of the above mentioned thlobarbituric acid compounds may be substituted for the 5-benzal-6-iminothiobarbituric acid of this example.

It will be apparent that the amounts of the foregoing agents may vary slightly with the different types of silver bromide emulsions, whether the toning agent is used in the emulsion or in the developing composition. However, the optimum quantities required for a particular composition can readily be determined by a. few simple tests. The'exa-mples are accordingly to be interpreted as illustrative rather than as limitations of the invention. It will be understood that these blue toning agents are equally useful in connection with mixe emulsions which containone or more addit nal silver halides, provided said emulsions contain a substantial amount ofsilver bromide. Thus, for example, these blue toners maybe used with gelatino silve'r chloro-bromide emulsions with the same good results as are obtained with the silver bromide emulsions defined in the specific examples.

Having now iully set forth and described our invention, what we claim as new and desire to secure by Letters Patent is:

1.. In a process for producing developed silver pictures in blue tones from silver bromide emulsions, the improvement which comprises developing said emulsions in the presence of a quantity of an organic compound corresponding to the formula co-NH R.- $=8 X= -N-Y -wherein R stands for a member of the group consisting of hydrogen, alkyl and anal; X stands for a member of the group consisting of 0 and NH; Y stands for a member of the group con- 5 sisting of hydrogen, alkyl and aryl, n being 1 in the caseof aral and 2 in the case of hydrogen and alkyl, sufilcient to produce blue toning of the develo d image.

2. A photographic material comprising a silver bromide emulsionlayer containinga quantity of an organic compound corresponding to the iormula C0--NH wherein R stands for a member of the group consisting of hydrogen, alkyl and aral; X stands for a member of the group consisting of O and NH; and Y standsior a member of the group consisting of hydrogen, alkyl and aryl, n being 1 inthe case of aral. and 2 in the case of hydrogen and alkyl, sufficient to produce blue toning in the development'oi the emulsion.

3. A photographic developer for development of silver bromide emulsions comprising developing agents and a quantity of an organic compound corresponding to the formula C0-NH Rel =8 X= 1-i-Y wherein R, stands for a member of the group consisting of hydrogen, alkyl and aral; X stands for a member of the group consisting of O and NH; and' Y stands for a member of the group consisting of hydrogen, alkyl and aryl, n being i in the case of are] and 2 in the case of hydrogen and alkyl, sufiicient' to produce blue toning of 40 silver bromide emulsions developed therein.

4. A photographic developer for development of silver bromide emulsions comprising developing agents and as ablue toning agent diethyla thiobarbituric acid.

5. A photographic developer for development of silver bromide emulsions comprising developing agents and as a blue toning agent dibutylthiobarbituric acid.

6. A photographic developer for development of silver bromide emulsions comprising develop-- ing agents and as a blue toning agent S-benzal- S-iminothiobarbituric acid.

' FRITZ DERSCH.

NEWTON HEIMBACH. 

